3d Lorentzian, Dynamically Triangulated Quantum Gravity

TL;DR

This paper explores a non-perturbative model of 3D quantum gravity using Lorentzian dynamical triangulations, revealing two distinct phases with different geometric behaviors.

Contribution

It introduces a Lorentzian 3D dynamical triangulation model that provides a background-independent framework for quantum gravity with distinct phases.

Findings

Identification of weak-coupling phase with semiclassical geometry

Discovery of strong-coupling phase with foam-like baby universes

Demonstration of background independence in the model

Abstract

The model of Lorentzian three-dimensional dynamical triangulations provides a non-perturbative definition of three-dimensional quantum gravity. The theory has two phases: a weak-coupling phase with quantum fluctuations around a ``semiclassical'' background geometry which is generated dynamically despite the fact that the formulation is explicitly background-independent, and a strong-coupling phase where ``classical'' space disintegrates into a foam of baby universes.